The present invention relates to a process of making granulates or multiparticulates which are useful, for example, in pharmaceutical dosage forms. In particular, the invention relates to a process for melt-extruding pharmaceutical agents with excipients to form multiparticulates suitable for inclusion in solid dosage forms such as capsules, tablets and the like.
It is known in the pharmaceutical art to prepare compositions which provide for controlled (slow) release of pharmacologically active substances contained in the compositions after oral administration to humans and animals. Such slow release compositions are used to delay absorption of a medicament until it has reached certain portions of the alimentary tract. Such sustained-release of a medicament in the alimentary tract further maintains a desired concentration of said medicament in the blood stream for a longer duration than would occur if conventional rapid release dosage forms are administered.
Over the years, several different methods of preparing controlled release pharmaceutical dosage forms have been suggested. For example, direct compression techniques, wet granulation techniques, encapsulation techniques and the like have been proposed to deliver pharmaceutically active ingredients to the alimentary tract over extended periods.
Melt granulation techniques have also been suggested to provide controlled release formulations. Melt granulation usually involves mechanically working an active ingredient in particulate form with one or more suitable binders and/or pharmaceutically acceptable excipients in a mixer until one or more of the binders melts and adheres to the surface of the particulate, eventually building up granules.
PCT International Publication No. WO 92/06679 discloses melt granulating methods for producing pellets containing therapeutically active substances. The method includes mechanically working a mixture containing the active substance in cohesive form with a binder having a melting point of 40-100.degree. C., while supplying sufficient energy to melt the binder and form "overmoist" spherical pellets and thereafter adding an additional cohesive substance while maintaining the mechanical working to finally produce dry pellets.
PCT International Publication No. WO 93/18753 also discloses another melt extrusion process for preparing sustained-release pellets. This method includes pelletizing a mixture containing drug in finely divided form and a binder which includes one or more water-insoluble-wax-like binder substances with a melting point above 40.degree. C. using a high shear mixer.
In the spite of the foregoing advances, a need for further alternatives in the field of controlled release formulations has been sought. The present invention addresses this need.